Inductively coupled plasma (ICP) etching of GaSb and InAs/GaSb super lattices were performed using Cl<sub>2</sub>/Ar plasma. The effects of GaSb of etching time, Cl<sub>2</sub>: Ar ratio and RF power on etching rates were investigated. It is found that the etching rates were relatively low when etch time was less than 2 min, After etching for 3 min, the etching rates was about 1.3 μm/min as a result of constant, also, the etching rate was increased monotonically with the increasing of Cl<sub>2</sub> proportion, and reaches at 4.14 μm/min when the Cl<sub>2</sub> concentration is 80%. In contrast, the peak value of etching rate of InAs/GaSb super lattices is 1.37 μm/min and the increase extent of etching rates of InAs/GaSb super lattices was much lower than that of GaSb, mainly owing to the insensitivity of InAs to the Cl<sub>2</sub> concentration. In addition, the etching rates of GaSb increased slowly with the increasing of RF power, which indicated the less efficiency influence of RF power on etching rate. The surface morphology of etched InAs/GaSb super lattices was characterized by WYKO HD3300 head measurement system, which suggested that the surface morphology was becoming rough with the increase of Cl<sub>2</sub> percentage. When the concentration reaches 60%, the surface morphology was unacceptable. The results showed that contrast to wet chemical etching, dry etching can form smoother pattern, which indicates the promising application in fabricating fine devices.
Platinum was deposited on unintentionally doped n-Al<sub>x</sub>Ga<sub>1-x</sub>N films grown by metal-organic chemical vapor deposition (MOCVD) to form MSM ultraviolet photodetectors. All devices were annealed for 10 min at different temperature in N<sub>2</sub> ambient. Results indicate that the generation of hillocks on the surface of Pt thin-film electrodes at the elevated temperatures due to relieving compressive stress affects the dark current directly. Dark current less than 10<i>pA</i> in the (-10V,10V) range was obtained from a device after annealing at 900°C. Both detectors show sharp spectral responsivity cutoff of about three orders of magnitude by 325nm and 315nm respectively.